The MK500 runs CE5.0, maybe your application is looking for something that needs to be post-loaded. I used to use the dependency walker (Dependency Walker (depends.exe) Home Page ) to determine what the missing dependencies might be. This is a 3rd party piece of software and is not endorsed by Zebra.
If you cycle the power on an MK500 it will cold boot. You need to use the a utility like StartupCtl StartupCtl Support & Downloads | Zebra to reinstall files from the \Application directory. Also see the MK500 product reference guide for more information: https://www.zebra.com/content/dam/zebra_new_ia/en-us/manuals/interactive-kiosks/mk500-product-reference-guide-en-us.pdf